Load bearing pallet and interlock

ABSTRACT

A load bearing pallet including two identical mold formed halves each having a load bearing surface and a plurality of relatively spaced supporting pads with an interlocking feature provided thereon and comprising a projection on the supporting pad extending thereacross and with an overhanging lip formed on one side thereof immediately over a draft opening, and with an opening immediately behind the projection formed for interference snap-lock and press fitted engagement therethrough of a like projection on a pallet half disposed in complimentary relation thereover.

United States Patent [.191

Lind 1451 Jul 23, 1974 [54] LOAD BEARING PALLET AND INTERLOCK 3,592,1457/1971 Petry 108/57 Inventor: Willard E. Lind c es Mich. 3,664,27l5/1972 Wolder 108/58 [73] Assignee: Jaw-Bar Plastics Corporation,Primary Examiner-Paul R. Gilliam Birmingham, Mich. Attorney, Agent, orFirmDale Austin Winnie [22] Filed: Sept. 14, 1972 [57] ABSTRACT PP Aload bearing pallet including two identical mold formed halves eachhaving a load bearing surface and [52] US. 01. 108/51, 108/58 ,aplurality of relatively Spaced Supporting P with 51 1m. 01 B65d 19/18imerlmking feature Provided thereon and Comprising 58 Field of Search108/51-58 a P i the Supporting Pald emnding there" 1 across and with anoverhanging lip formed on one side [56] References Cited thereofimmediately over a draft opening, and with an UNITED STATES PATENTSopening immediately behind the projection formed for interferencesnap-lock and press fitted engagement g therethrough of a likeprojection on a pallet half dis- 3:307:504 3/1967 :532: n 108/58 posedin complimentary relation thereover. 3,404,642 10/1968 Belcher et al108/58 X 4 Claims, 10 Drawing Figures I LOAD BEARING PALLET ANDINTERLOCK BACKGROUND OF THE INVENTION Most load bearing pallets, whichare used with fork lift trucks, are made of wood slats nailed to crossmembers, on each side, and are usually of unfinished lumber so roughlyand crudely made that they are generally expendable after a relativelyshort period of time. Normally they are made so that fork lift entry ispossible from only two opposite sides and since they are seldom paintedor treated in any way they are prone to collect and retain moisturewhich results in mildew, rot and their ultimate deterioration.

Although efforts have been made to make pallets out of other moredurable and longer lasting materials, the expense and/or added weight ofthe pallets have proven impractical on any large scale basis.

Aluminum and plastic materials have been tried, be cause of theirrelative light weight, but with these materials another problem has beenthat only single faced pallets can be made, due to the mold formingprocess from which they are derived. This, in turn means even furtherexpense in fastening and retaining two complementary pallet halvestogether, if a two faced pallet is desirable.

SUMMARY OF THE PRESENT INVENTION The present invention is directed to atwo faced pallet' having four way entry, which is made of a light weighthigh impact resistant plastic material, and which is mold formed toinclude a particularly new and model means of interlocking'opposite andrelatively identical pallet halves together without the use of separateand distinct fastener means.

The basic pallet form is of an open honey cone structure with supportingpads formed at and between its corners which include the palletinterlock feature. The interlock on each pad includes a projectionextending across the pad which has an overhanging lip provided on theoutermost end of one side, immediately over a relatively narrow draftopening beside the projection which enables the overhanging lip to bemold formed right on the cross projection.

There is, in turn, an opening provided immediately beside and behind thepad projection which is formed to receive in an interference andsnap-lock fitted engagement therethrough a like pad projection of anidentical pallet half complementarily disposed thereover for pressfitted interlocking engagement therewith.

As a consequence, identical pallet halves, with like supporting pads,including complementarily disposed interlocking features are receivedone over the other, in back-to-back relation, and may be force fittedinto a secure and positive engagement to provide a two faced lightweight pallet which allows four way entry and one which will not warp orrot and is capable of steam cleaning as and when desired.

DESCRIPTION OF THE DRAWING FIGURES FIG. 1 is a side edge view of one endof a pallet made in accord with the teachings of the present invention.

FIG. 2 is a top plan view of one corner of the pallet.

FIG. 3 is a perspective view of a whole pallet includ-' ing theinterlock feature of the present, invention.

FIG. 4 is an enlarged cross-sectional view taken through one of theinterlocking lugs or pads of the pallet shown in the previous drawingfigures.

FIG. 5 is a bottom plan view of one of the interlocking parts, in and ofitself.

FIG. 6 is a top plan view of the same interlocking part.

FIG. 7 is a side elevational view of the interlocking part with certainfeatures shown in dotted outline as they are therewith.

FIG. 8 is a front face elevational view of the interlocking part, againwith certain features shown in dotted outline as they are therewithin.

FIG. 9 is a side elevational view of two of the interlocking parts, asprovided on like pallet halves and disposed relative to each otherimmediately prior to being press fitted into locking relationship witheach other.

FIG. 10 is a side elevational view of the same two parts as shown in theimmediately preceeding drawing DETAILED DESCRIPTION OF THE ILLUSTRATEDEMBODIMENT The first three drawing figures show a load bearing pallet 10made up of two identical halves l2 and 14 which are joined and lockedtogether by means of special locking lugs 16.

Each pallet half is made of a polyprope'n plastic such as polypropolene,polyethelene or polystyrene material in an open waffle pattern whichincludes transversely crossed ribs 18 and 20 that are about A of an inchdeep and with a wall thickness of about A of an inch in the ribs and thelocking lubs 16.

The pallet halves are formed with a narrowing taper or draft downwardlyfrom their face sides, to facilitate their mold form release, as isshown princiapply in FIG. 4, and to include three locking lugs 16 alongeach side edge, and one centrally, for a total of nine locking lugs inall.

As joined and locked together the pallet halves provide a two facepallet having four way entry, that is from any accessible side, by afork lift truck or like pallet lifting and moving means. And, they areimpact tested and approved, will not warp or rot, can be steam cleaned,are light weight (about 35 pounds) and have a static load bearingcapacity of 14,000 pounds which enables their use in at least four highstacks.

Of particular note are the locking lugs 16 which will hereafter bedescribed in further detail. Since each pallet half 12 and 14 isidentical, the locking lugs are identical and identically located sothat they are relatively aligned when one pallet half is turned over andplaced on another pallet half.

The locking lugs include a generally square box sectioned form, about 3inches deep, with opposite side walls 22, 24 and 26, 28 including abouta 5 draft. They also include a bottom wall 30 within which is providedtwo openings 32 and 34, one on each side of a projection 36 that extendsbetween the relatively opposite side walls 26 and 28.

The larger of the two openings, which is identified as 32, is relativelybehind the projection 36 and is formed on its outer side to include achamfer of about 30 around three of its side edges and to have astraight, no draft, edge inclusive of the back wall 38 of the projection36. It also includes on its inner side edge, opposite v the projection36, a rib 40 which stands about .one-

fourth of an inch high and extends in parallel spaced relation to theprojection on the inner side of the bot tom wall 30;

For reasons later more fully appreciated, the rib 40 has about a 15camfer on each edge of its extreme end ity of relatively spaced membersformed therewith inerand about a 2 draft along its side edge borderingthe opening 32.

The projection 36, that is formed from the bottom wall 30, is not solidbut inclusive of an opening 42 within its underside and admin hole 44centrally of an inch apart from the bottom wall 30 and is formed toinclude a lip 46 near its outermost end which extends relative over thesmaller bottom wall opening 34 on its other side. r

The back corners of the projection 36 and the front corners of the lip46 each include about a 45 chamfer and the top or end wall of theprojection includes about is of substantially the samewidth as theopening 32 relatively behind it, except for the lip 46. Accordingly whentwo locking lugs,-or pallet halves with locking r lugs, are disposed asshown in FIG. 9, their back walls 38 are relatively aligned against eachother and the chamfered edge of their lips 46 lie on the chamfered edgeof the opening 32.

thereof through its top wall. It extends a little under."/s

locking said halves together and relatively spacing said load bearingsurfaces apart, said interlocking members comprising; a depending formunder said load bearing surface and including a bottom wall providing asupporting pad, a projection on said supporting pad extending relativelythereacross near one side thereof and having an overhanging lipprovidedon the outermost end of the outermost side thereof, an opening providedin said supporting pad next adjacent and relatively behind saidprojection near the other side thereof, and of a relatively like breadthand width thereto exclusive of said overhanging lip, and a rib railformed on said bottom wall on the side edge of said opening opposite andin parallel spaced relation to said projection extending within saiddepending form, said lip and rib rail being formed for a yieldinginterference fit with a corresponding rib rail and lip, respectively, ona like depend- Since the shorter ends of both the projections 36 and theopenings 32 are also chamfered there is a natural centering of theprojections within the openings for rel-- ative alignment of the twopallet halves being joined together, andv since the side edge corners'ofthe projections are chamfered and the corners of the opening 32 areradiused, as shown, it follows that with a sufficient impact force,properly applied, the locking lug projections 36 may be forced throughthe openings 32, for the interlock shown in FIGS. 4 and 10, with theprojection member lips 46 engaged over the ends of the ribs 40.

As previously mentioned, both the underside of the ing form received incomplimentary relation and into pressed engagement therewith, saidpallet halves being of molded plastic material and said supporting padshaving a second opening formed therein immediately under said overhanging lip for mold form manufacturing ease and providing addedelasticity in the interlocking use thereof, said first mentioned openinghaving the side edges therearound chamfered on the outer disposed sidethereof and said projection being chamfered on the end thereof forcomplimentary alignment therebetween preceeding the pressed engagementof said projection therethrough, said lip and rib rail having acomplimentary chamfer provided on the underside of said lip and on theextreme end wall of said rib rail for closer fitting interengagementtherebetween.

2. The load bearing pallet of claim 1, said plastic material of saidpallet halves and inclusive of said overhanging lip and rib rail beingretained at a temperature of 80 to 1 10 for added pliability andlubricity condusive to the press fitted interengagement required thereamount as the thickness, or standing height of the ribs 40, togetherwith the thickness of the bottom wall 30,

so that there is a secure and tight interfit between the, lips 46 andribs 40 and the assurance of a positive and r relatively fixedengagement between each pair of interengaged locking lugs.

In actual assembly the pallet material, and more parlips to provide forany necessarydrainageat each end,

in the final assembly, and, as mentioned, the locking projections 36themselves are provided with drain holes 44 so that no accumulation ofwater will catch and stagnate aroundthe pallet interlocks.

In conclusion, although the interlocking system shown has been designedfor use with load bearing palj between. v 3. A snap lock interferencefitted connection for interlocking different plastic molded partstogether, and comprising: two identical halves each having a loadbearing surface and a plurality of relatively spaced members formedtherewith interlocking said halves together and relatively spacing saidload bearing surfaces apart, said interlocking members comprising adepending form under each of said plastic molded parts and I including abottom wall providing a supporting pad, a

ticularly the locking lugs 16, are maintained at between a projection onsaid supporting pad extending relatively thereacross near one sidethereof and having an overhanging lip provided on the outermost end ofthe outermost side thereof, an opening provided in said supporting padnext adjacent and relatively behind said projection near the other sidethereof, and of a relatively like breadth and width thereto exclusive ofsaid overhanging lip, and a rib rail formed on said bottom wall on theside edge of said opening opposite and in parallel spaced relation tosaid projection extending within said depending form, said lip and ribrail being formed for a yielding interference fit with a correspondingrib rail and lip, respectively on a like depending form receivedincomplimen'tary relation and into pressed engagetary chamfer providedon the underside of said lip and on the extreme end wall of said ribrail for closer fitting interengagement therebetween.

4. The snap lock interference fitted connection of claim 3, said plasticmaterial of said molded parts and inclusive of said overhanging lip andrib rail being retained at a temperature of to 1 10 for added pliabilityand lubricity condusive to the press fitted interengagement requiredtherebetween.

1. A load bearing pallet including two identical halves each having aload bearing surface and a plurality of relatively spaced members formedtherewith inerlocking said halves together and relatively spacing saidload bearing surfaces apart, said interlocking members comprising; adepending form under said load bearing surface and including a bottomwall providing a supporting pad, a projection on said supporting padextending relatively thereacross near one side thereof and having anoverhanging lip provided on the outermost end of the outermost sidethereof, an opening provided in said supporting pad next adjacent andrelatively behind said projection near the other side thereof, and of arelatively like breadth and width thereto exclusive of said overhanginglip, and a rib rail formed on said bottom wall on the side edge of saidopening opposite and in parallel spaced relation to said projectionextending within said depending form, said lip and rib rail being formedfor a yIelding interference fit with a corresponding rib rail and lip,respectively, on a like depending form received in complimentaryrelation and into pressed engagement therewith, said pallet halves beingof molded plastic material and said supporting pads having a secondopening formed therein immediately under said over hanging lip for moldform manufacturing ease and providing added elasticity in theinterlocking use thereof, said first mentioned opening having the sideedges therearound chamfered on the outer disposed side thereof and saidprojection being chamfered on the end thereof for complimentaryalignment therebetween preceeding the pressed engagement of saidprojection therethrough, said lip and rib rail having a complimentarychamfer provided on the underside of said lip and on the extreme endwall of said rib rail for closer fitting interengagement therebetween.2. The load bearing pallet of claim 1, said plastic material of saidpallet halves and inclusive of said overhanging lip and rib rail beingretained at a temperature of 80* to 110* for added pliability andlubricity condusive to the press fitted interengagement requiredtherebetween.
 3. A snap lock interference fitted connection forinterlocking different plastic molded parts together, and comprising:two identical halves each having a load bearing surface and a pluralityof relatively spaced members formed therewith interlocking said halvestogether and relatively spacing said load bearing surfaces apart, saidinterlocking members comprising a depending form under each of saidplastic molded parts and including a bottom wall providing a supportingpad, a projection on said supporting pad extending relativelythereacross near one side thereof and having an overhanging lip providedon the outermost end of the outermost side thereof, an opening providedin said supporting pad next adjacent and relatively behind saidprojection near the other side thereof, and of a relatively like breadthand width thereto exclusive of said overhanging lip, and a rib railformed on said bottom wall on the side edge of said opening opposite andin parallel spaced relation to said projection extending within saiddepending form, said lip and rib rail being formed for a yieldinginterference fit with a corresponding rib rail and lip, respectively ona like depending form received in complimentary relation and intopressed engagement therewith, said supporting pads having a secondopening formed therein immediately under said overhanging lip for moldform manufacturing ease and providing added elasticity in theinterlocking use thereof, said first mentioned opening having the sideedges therearound chamfered on the outer disposed side thereof and saidprojection being chamfered on the end thereof for complimentaryalignment therebetween preceeding the pressed engagement of saidprojection therethrough, said lip and rib rail having a complimentarychamfer provided on the underside of said lip and on the extreme endwall of said rib rail for closer fitting interengagement therebetween.4. The snap lock interference fitted connection of claim 3, said plasticmaterial of said molded parts and inclusive of said overhanging lip andrib rail being retained at a temperature of 80* to 110* for addedpliability and lubricity condusive to the press fitted interengagementrequired therebetween.